Idea for the competition: Low power snake game for harmattan. If you make a black overlay widget like those used for video playback (direct playback to framebuffer) then whatever you print to the framebuffer shows through any black area, and also the low power screen. Thus it would be possible to make games for the lock screen like space invaders or snake, controlled with accelerometer.

I won't have time to play with this idea so anybody that finds it interesting can take it on.